In the related art, a decolorable toner is decolored when heated at a temperature equal to or higher than a predetermined temperature. Accordingly, an image forming apparatus is capable of printing using the decolorable toner, and a decoloring apparatus is capable of decoloring an image printed with the decolorable toner. Since a decolored sheet can be reused for a new printing process, it is economical for a user and it is possible to reduce an environmental burden. In order to promote reuse of such a sheet, there is demand to give value to the user who reuses the sheet when using the image forming apparatus.